The present invention relates to an apparatus for filling bags with a material and for sealing them.
The apparatus for filling the bags has already been suggested in U.S. Pat. No. 4,108,300. Each bag used on this apparatus comprises a laminate of a plastic film over a paper or an aluminum foil sheet and is previously sealed along three edges thereof, as shown in FIG. 1 attached hereto. Further, the bag 1 may be a gusseted bag wherein its bottom is folded in a gusset style so as to be capable of standing by itself.
Such an apparatus is shown in FIGS. 2 and 3. A pair of chain conveyors 2 which are disposed in parallel vertical planes is supported on five pairs of sprockets 3. Each pair of the sprockets is mounted on an axle 4. Reference numerals 5 and 6 are a motor and an index device respectively, and the axles 4 can be intermittently rotated thereby. Grippers 7 are mounted at equidistant intervals on the chain conveyors 2 and are adapted to grip upper portions of the bags 1. Numerals 8 and 9 are rails for guiding the grippers 7 and a magazine for stocking the bags 1 respectively. A bag taking out member 10 serves to take out the bags 1 from the magazine 9 one by one and to transfer them to regions between the opposite grippers 7, 7. Numeral 11 is a bag opening member and possesses known vacuum cups by which the bags 1 gripped between and by the grippers 7, 7 are opened. At this time, the opposite grippers 7, 7 approach to each other so as to assist the bags 1 in opening, and the opened bags 1 are carried while kept opened. Numeral 12 is a filling device for a material and numeral 13 is a sealing device for the bags 1. The bags 1 which have been filled with the material and have been sealed are then discharged as bag products 1a through a belt conveyor 14.
It will be understood that the efficiency of such an apparatus for filling the bags can be improved by carrying the bags 1 along two or more carrying lines. However, the attempt to carry the bags 1 along a plurality of the carrying lines in the shown apparatus is not so different from a combination of a plurality of the same apparatuses, though the motor 5 and a link mechanism for the bag taking out device 10 can be utilized in common.
In addition, in the case that the apparatus is run at a high speed, an insecure bag taking out operation or an insecure bag grip of the grippers will be brought about sometimes, which fact will lead to an inaccurate bag grip between the grippers At this time, the work of the material filling must be interrupted. In the conventional apparatuses, however, any mechanism for judging whether or not the bags are surely gripped is not equipped, and there has not been suggested any method for filling, with the material, all the bags on the plural carrying lines except one bag.